The cellular standards, in particular those supporting long term evolution (LTE) standard, are beginning to face the fact that different types of user equipment are operating within the wireless networks. A special interest is directed to so-called machine-type communication devices (MTC), which behave differently than mobile handsets.
As part of the standardization activities in Release 13 for such MTC devices special channels and information blocks are foreseen.
One of the key elements is the definition of system information blocks (SIB). As part of that system information blocks dedicated for MTC devices (M-SIBs) are suggested. System information is known to be distributed in different system information blocks, which are transmitted during one broadcast channel modification period.
Further MTC devices are separated in low complexity and low complexity devices with Enhanced Coverage UEs. Low complexity is achieved by placing in bandwidth reception capabilities lower demands than for normal devices, i.e. those devices are only required to receive 1.4 MHz radio frequency bandwidth. The low complexity devices for enhanced coverage are characterized that they are receiving or transmitting information in a repetitive manner and the receiver performing coherent average so that additional reception gain is achieved i.e. these are also low complexity devices applying coverage enhancements techniques. These two categories of devices are defined in specification 3GPP TR 36.888 V12.0.0, which content is incorporated here by reference.
Both of these types of devices address different use cases and hence place different burdens on the SIB handling. It is in particular preferable to address both types of devices with one common set of M-SIBs.
The enhanced coverage devices typically considered as meters are static/semi-static and gain their enhanced coverage by repetitive reading of the related information. This is also applicable for the SIBs itself. The number of repetitions for enhanced coverage may be very high, which leads to high latencies for receiving of all system information in an UE. Times of 10.24 s are assumed to be acceptable for these devices.
On the other hand generally SIB1 needs to be read in order to know if in at least one of the other system information blocks a change has happened, which is indicated by the so-called BCCH value tag. For enhanced coverage devices it is by now a challenge to successfully decode the SIB1 during one broadcast channel modification period.
However, it is not only the latency but also the corresponding reading time and consequently the battery consumption which causes an inappropriate operation of such devices. In particular repetitive reading during operation for e.g. acquiring the BCCH value tag or even the entire SIB structure leads to additional power consumption. This is in particular true in case of SIB reading operations of the UEs which are in vain, due to the fact that the SIB1-reading could not be finished during the broadcast channel modification period.
It is therefore the goal of present invention to overcome the mentioned disadvantages and to propose a solution for an improved transmission of system information from a base station to a user equipment.
Further alternative and advantageous solutions would, accordingly, be desirable in the art.